# main_module.py  
  
# 导入模块  
import math_operations as mo  
import string_manipulations as sm  
import list_utilities as lu  
  
# 调用math_operations.py中的函数和变量  
print(f"PI: {mo.PI}")  
print(f"E: {mo.E}")  
print(f"add(3, 4): {mo.add(3, 4)}")  
print(f"multiply(3, 4): {mo.multiply(3, 4)}")  
  
# 调用string_manipulations.py中的函数和变量  
print(f"greeting: {sm.greeting}")  
print(f"farewell: {sm.farewell}")  
print(f"concatenate('Hello', 'World'): {sm.concatenate('Hello', 'World')}")  
print(f"reverse_string('Hello'): {sm.reverse_string('Hello')}")  
  
# 调用list_utilities.py中的函数和变量  
print(f"empty_list: {lu.empty_list}")  
print(f"numbers: {lu.numbers}")  
print(f"append_to_list(numbers, 6): {lu.append_to_list(lu.numbers[:], 6)}")  # 使用[:]避免修改原列表  
print(f"sum_list(numbers): {lu.sum_list(lu.numbers)}")